Impact of the Complex Terrain in Beijing on Formation of Low-Level Jets  

作　　者：Li’ao ZHOU Chenggang WANG Shiguang MIAO Ju LI 

机构地区：[1]School of Atmospheric Physics,Nanjing University of Information Science&Technology,Nanjing 210044 [2]Institute of Urban Meteorology,China Meteorological Administration,Beijing 100089 [3]Key Laboratory of Urban Meteorology,China Meteorological Administration,Beijing 100089

出　　处：《Journal of Meteorological Research》2024年第1期138-150,共13页气象学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(41975011)。

摘　　要：This study investigated how the Taihang Mountains and the Yanshan Mountains affect low-level jets(LLJs)in the Beijing area,based on conventional radiosonde observations from Nanjiao Observatory(2016–2017)and high-resolution Weather Research and Forecasting–Advanced Research WRF(WRF-ARW)model simulations.Analysis of radiosonde observations indicated that LLJs in the study area are mainly from the southwest and northwest directions,with occurrence frequency of 44.6%and 33.0%,respectively.Southwest(northwest)LLJs are aligned parallel(perpendicular)to the orientation of the Taihang Mountain Range.Terrain sensitivity experiments using the WRF-ARW model were then conducted to examine the effects of terrain forcing on the northwest and southwest LLJs,with adopted terrain heights of 100%and 50%.The results showed that for northwest LLJs,reduction in the elevation of the Taihang Mountain Range led to weakening of jet intensity by approximately 20%and reduction in jet maximum height by approximately 250 m;lowering the Yanshan Mountain Range had minor influence on the northwest LLJs,with only a 5.2%reduction in intensity and no substantial change in jet maximum height.For southwest LLJs,reduction in the elevation of both the Taihang and Yanshan Mountain ranges resulted in minor changes in the intensity and height of the jets.Further analysis revealed that the topography in the Beijing area could modulate the height and intensity of the stable layer by altering the inversion structure within the boundary layer.The LLJs can develop rapidly within the stable layer,and both the location and the scale of the jet core exhibited reasonable agreement with the extent of the stable layer.

关 键 词：low-level jets(LLJs) mesoscale numerical simulation terrain forcing 

分 类 号：P461.3[天文地球—大气科学及气象学]